In making hardware fixtures, such as bolt snaps, the body portion forming the hook and the barrel for the spring biased keeper has heretofore generally been cast from gray iron or malleable iron by a foundry operation. In some instances, such fittings may be cast from brass or bronze. To produce the body portion of the bolt snap in this fashion, a foundry is needed to melt the gray iron, malleable iron, or brass. The molten metal is poured into sand molds having the desired shape of the body to be used for the bolt snap. After this foundry operation, the body is machined and cleaned or burnished. The keeper is then assembled into a machined bore on the body to form the releasable closure for the hook cast as part of the body. A swivel element or eye, when used, is then assembled onto the cast body for supporting the bolt snap on an external structure during use. This manufacturing procedure has been used for many years in making bolt snaps and other similar snaps for hardware products.
When using sand molds and other cast iron foundry procedures, several difficulties are encountered which add to the overall cost of the end product, especially a high production item such as a hardware fixture. Relatively small hardware fixtures add complexity to the foundry operation. In addition, coring and handling of small cast iron components becomes somewhat difficult. Voids and other defects in the foundry operation can cause scrap and rejection of the molded components. When a bolt snap body is formed by a foundry operation, it is difficult to determine the load supporting capacity of the integral hook. It has heretofore been difficult to rate the various bolt snaps and other hardware fixtures having a body with an integral hook. Consequently, the consuming public is not aware of the operating capacity of a hardware snap. If the bolt snap is tested in a machine to determine its point of failure, there is no assurance that this point of failure will be reached uniformly by various other snaps or hardware components employing the same metal and the same foundry procedures. In addition, cast iron has a relatively low shock resistance which can cause fracture of the body portion, especially in the area of the free end hook, by inadvertent blows.
Since a foundry operation requires substantial capital investment, it is difficult to intall plants at dispersed sites. Thus, if manufacturing of bolt snaps is to take place in various geographical locations, a central foundry is used with the component parts being shipped to the various locations for final assembly and/or machining. This adds to the transportation cost which can be prohibitive for relatively low profit items such as hardware fixtures. When using a foundry operation, it is difficult to heat treat the cast body of a bolt snap to provide improved strength characteristics. It is also difficult to provide certain types of finishes which may be decorative and desirable for marketing purposes. Adding further to the cost of the foundry process is the cost of pollution control equipment which is necessary to meet governmental standards. In some instances die casting procedures are employed for the body of hardware snaps. Die casting also is limited with respect to the metals which can be used and the physical properties which can be obtained.